From 0b378942c4f1b79cb65967f2d3466728ca1c8d5b Mon Sep 17 00:00:00 2001 From: Jason Dillaman Date: Wed, 22 Apr 2015 11:27:35 -0400 Subject: [PATCH] librbd: updated cache max objects calculation The previous calculation was based upon the image's object size. Since the cache stores smaller bufferheads, the object size is not a good indicator of cache usage and was resulting in objects being evicted from the cache too often. Instead, base the max number of objects on the memory load required to store the extra metadata for the objects. Fixes: #7385 Backport: firefly, hammer Signed-off-by: Jason Dillaman --- src/librbd/ImageCtx.cc | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc index 5f9ba89546e21..c7174864932b4 100644 --- a/src/librbd/ImageCtx.cc +++ b/src/librbd/ImageCtx.cc @@ -226,10 +226,9 @@ namespace librbd { if (object_cacher) { uint64_t obj = cache_max_dirty_object; if (!obj) { - obj = cache_size / (1ull << order); - obj = obj * 4 + 10; + obj = MIN(2000, MAX(10, cache_size / 100 / sizeof(ObjectCacher::Object))); } - ldout(cct, 10) << " cache bytes " << cache_size << " order " << (int)order + ldout(cct, 10) << " cache bytes " << cache_size << " -> about " << obj << " objects" << dendl; object_cacher->set_max_objects(obj); } -- 2.39.5